51661111653 has 24 divisors (see below), whose sum is σ = 75775474008. Its totient is φ = 33909829632.

The previous prime is 51661111651. The next prime is 51661111669. The reversal of 51661111653 is 35611116615.

It can be written as a sum of positive squares in 4 ways, for example, as 33457165569 + 18203946084 = 182913^2 + 134922^2 .

It is not a de Polignac number, because 51661111653 - 2¹ = 51661111651 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51661111651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 310951 + ... + 447227.

It is an arithmetic number, because the mean of its divisors is an integer number (3157311417).

Almost surely, 2^51661111653 is an apocalyptic number.

It is an amenable number.

51661111653 is a deficient number, since it is larger than the sum of its proper divisors (24114362355).

51661111653 is a wasteful number, since it uses less digits than its factorization.

51661111653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136933 (or 136930 counting only the distinct ones).

The product of its digits is 16200, while the sum is 36.

The spelling of 51661111653 in words is "fifty-one billion, six hundred sixty-one million, one hundred eleven thousand, six hundred fifty-three".